This invention relates to a method for modifying fibers.
For the purposes of preventing fibers from fluffing, improving tensile strength and wear resistance of fibers, imparting static resistance and water absorption to fibers, and providing good hand or texture of fibers such as smooth and dry feeling to fibers, there has been proposed a method called “imitation linen finishing” wherein viscose is attached to fibers and is coagulated and regenerated, followed by rinsing with water and drying to cover the fiber surfaces with regenerated cellulose.
In this connection, however, the method of modifying fibers by coverage with viscose-derived, regenerated fibers includes the steps of applying to fibers a solution, i.e., viscose, obtained by dissolving in a sodium hydroxide aqueous solution cellulose xanthate which is prepared by degenerating cellulose with highly toxic carbon disulfide, and subsequently coagulating and regenerating the cellulose. This presents a problem that in the steps of preparing cellulose xanthate and coagulating and regenerating the cellulose, workers undergo exposure to carbon disulfide. In addition, the regenerated cellulose per se used for the coverage according to this fiber modifying method is unsatisfactory with respect to water absorption, thus causing the problem in that improvements in static resistance, water absorption, shrink proofing are not satisfactory.
Further, with the “imitation linen finishing”, an alkali aqueous solution is used, which needs the step of neutralization with an acid for coagulation, thus involving a difficulty in modifying fibers that are poor in resistance to alkali.
To solve the problem on the modification of fibers by coverage with viscose-derived, regenerated cellulose, a method of covering fiber surfaces with regenerated cellulose has been proposed. In the method, cellulose per se is dissolved in a sodium hydroxide aqueous solution and attached to fibers, followed by coagulation and regeneration (JP-A 61-252369).
However, this method needs not only the dissolution of cellulose in a sodium hydroxide aqueous solution at low temperature, but also the use of cellulose of the type which has a reduced degree of crystal structure sufficient to increase solubility, e.g. cellulose that is obtained by acid hydrolyzing wood pulp and grinding it in a ball mill, or regenerated cellulose that is prepared from viscose, thus imposing limitation on the method.